Re-quantization device having noise shaping function, signal compression device having noise shaping function, and signal transmission device having noise shaping function

Abstract

What is provided is a subtractor, as a re-quantization device, which is configured to detect re-quantization noise, a discrete time filter which is configured to perform frequency weighting on the detected re-quantization noise, an adder which is configured to add an additional signal to quantization noise, and an additional signal selector which is configured to select a value at the present time of a column of an additional signal for minimizing the magnitude of quantization noise having been subjected to frequency weighting evaluated one sampling or more later.

What is claimed is: 
     
       1. A re-quantization device having a noise shaping function, the re-quantization device comprising:
 a subtractor which is configured to input a high resolution signal being a pulse code modulation signal and output a low resolution signal being a pulse code modulation signal to detect re-quantization noise which is a difference between the high resolution signal and the low resolution signal; 
 a discrete time filter which is configured to perform frequency weighting; 
 a quantizer; 
 an adder which is configured to add an additional signal to an output signal of the quantizer; and 
 an additional signal selector which is configured to generate the additional signal, 
 wherein the high resolution signal is input to the quantizer, 
 a signal obtained by adding the additional signal to the output signal of the quantizer is set to be the low resolution signal, 
 the re-quantization noise is input to the discrete time filter, 
 the additional signal is calculated on the basis of values of the output signal of the discrete time filter from a present time to a finite step future, 
 the additional signal has 31 or less values, and 
 these processes are executed through batch processing. 
 
     
     
       2. The re-quantization device having a noise shaping function according to  claim 1 , wherein real-time processing is executed by delaying the low resolution signal by a finite step and outputting the low resolution signal. 
     
     
       3. The re-quantization device having a noise shaping function according to  claim 2 , wherein the additional signal has three values. 
     
     
       4. The re-quantization device having a noise shaping function according to  claim 2 , wherein a resolution of the low resolution signal is lower than a resolution of the high resolution signal. 
     
     
       5. A signal compression device having a noise shaping function, the signal compression device comprising:
 the re-quantization device having a noise shaping function according to  claim 2 , the re-quantization device inputting a high resolution signal being a pulse code modulation signal and outputting a low resolution signal being a pulse code modulation signal; and 
 a signal compressor which is configured to convert the low resolution signal into compressed data, 
 wherein the high resolution signal is used as an input signal, and the compressed data is used as an output signal. 
 
     
     
       6. A signal transmission device having a noise shaping function, the signal transmission device comprising:
 the signal compression device according to  claim 5 , the signal compression device inputting a high resolution signal being a pulse code modulation signal and outputting compressed data; and 
 a transmitter which is a means for transmitting the compressed data. 
 
     
     
       7. The re-quantization device having a noise shaping function according to  claim 1 , wherein the additional signal has three values. 
     
     
       8. The re-quantization device having a noise shaping function according to  claim 1 , wherein a resolution of the low resolution signal is lower than a resolution of the high resolution signal. 
     
     
       9. A signal compression device having a noise shaping function, the signal compression device comprising:
 the re-quantization device having a noise shaping function according to  claim 1 , the re-quantization device inputting a high resolution signal being a pulse code modulation signal and outputting a low resolution signal being a pulse code modulation signal; and 
 a signal compressor which is configured to convert the low resolution signal into compressed data, 
 wherein the high resolution signal is used as an input signal, and the compressed data is used as an output signal. 
 
     
     
       10. A signal transmission device having a noise shaping function, the signal transmission device comprising:
 the signal compression device according to  claim 9 , the signal compression device inputting a high resolution signal being a pulse code modulation signal and outputting compressed data; and
 a transmitter which is a means for transmitting the compressed data. 
 
 
     
     
       11. A re-quantization device having a noise shaping function, the re-quantization device comprising:
 a subtractor which is configured to input a high resolution signal being a pulse code modulation signal and a known noise signal being a pulse code signal and outputs a signal obtained by synthesizing a low resolution signal being a pulse code modulation signal and the known noise signal to detect re-quantization noise which is a difference between the high resolution signal and a sum of the low resolution signal and the known noise signal; 
 a discrete time filter which is configured to perform frequency weighting; 
 a quantizer; 
 an adder which is configured to add an additional signal to an output signal of the quantizer; and 
 an additional signal selector which is configured to generate the additional signal, 
 wherein the high resolution signal is input to the quantizer, 
 a signal obtained by adding the additional signal to the output signal of the quantizer is set to be the low resolution signal, 
 the re-quantization noise is input to the discrete time filter, 
 the additional signal is calculated on the basis of values of the output signal of the discrete time filter from a present time to a finite step future, 
 the additional signal has 31 or less values, and 
 these processes are executed through batch processing. 
 
     
     
       12. The re-quantization device having a noise shaping function according to  claim 11  wherein the additional signal has three values. 
     
     
       13. The re-quantization device having a noise shaping function according to  claim 11 , wherein a resolution of the low resolution signal is lower than a resolution of the high resolution signal. 
     
     
       14. A signal compression device having a noise shaping function, the signal compression device comprising:
 the re-quantization device having a noise shaping function according to  claim 11 , the re-quantization device inputting a high resolution signal being a pulse code modulation signal and outputting a low resolution signal being a pulse code modulation signal; and 
 a signal compressor which is configured to convert the low resolution signal into compressed data, 
 wherein the high resolution signal is used as an input signal, and the compressed data is used as an output signal.